Electric cooktop appliance



FIG. 1 is a top perspective view of an electric cooktop appliance showing my new design;

FIG. 2 is a side elevational view thereof; and,

FIG. 3 is an end elevational view thereof.

The portion shown in broken lines in FIGS. 1-3 is shown for illustrative purposes only and forms no part of the claimed design. The undisclosed bottom is flat and unornamented. 

The ornamental design for an electric cooktop appliance as applied to an electric cooking appliance, as shown and described. 